Improvement in lamp-chimneys



i R. s. MERRILL.

Lamp Chimney.

' Patented Jan. 17, 1871.7

WI TKESSES.

N.FETERS. FHDTO-LITHOGRAPN UNITED STATES PATENT Tricia RUFUS S. MERRILL, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO HIMSELF, IVILLIAM B. MERRILL, AND JOSHUA MERRILL, OF SAME PLACE.

IMPROVEMENT IN LAM P-CIiHMNEYS.

Specification forming part of Letters Patent No. lilil,0 73, dated January 17,1871.

To all 1072,0112 it may concern Be it known. that I, Burns S. MERRILL, of Boston, in the county of Suffolk and State of Massachusetts, have invented certain new and useful Improvements in Lamp-Chimneys, of which the following is a specification.

My invention relates to slip-chimneys, so called, for Argand burnersthat is to say, chimneys havinga contracted neck, and fitting at their lower end within external springs attached to the burner. That portion of the chimney slipped within or between thesprings, which, for convenience sake, I will term the base of the chimney, has heretofore been made cylindrical, or of the same diameter throughout its length. The use of a chimney with its base thus formed is attended with considerable disadvantage, arising, mainly, from the fact that the springs, when the lamp is jostled or shaken about-in a railway-car, for instancewill not prevent the chimney from rising or being gradually thrown up away from the burner until it finally slips out from between the springs and falls from the lamp. This arises from the fact that the base is cylindrical, and the springs therefore exercise the same pressure upon its straight or perpendicular sides, whether it be inserted for a greater or less distance between the springs; and consequently when the chimney has been raised from the burner by being tilted or jostled, the springs not only have no power to compel its return to its first position, but, indeed, actually prevent it.

My object has been to overcome the difficulty referred to, and this I have accomplished by giving the base of the chimney a conical form, the greatest diameter being at the bottom, and by combining with it external springs, between which theconical base is slipped. In this manner two distinct effects are produced, Viz:

First. Suppose the chimney, through any accident or mischance, to be raised from the base of the burner, the springs will press upon the chimney with an increased force proportionate to the distance the chimney is lifted from the base of the burner. This is due to the fact that when the chimney is in its low est position the springs grasp the smallest part of the conical base, and consequently l in proportion as the chimney is raised the diameter of ;;that portion of it with which the springs are iii contact will be increased.

Second. T e chimney tends continually, in case it'is rai ed from the base of the burner, to return to ts lowest position, this being due to the pressire of the springs upon the inclined or 001 'cal surface of the chimney-base, which at all imes has atendency to crowd the chimney doytn into place. The combined result is that t e chimney is held most securely in place, and} its tendency to separate from the burner and to slip up and out from between the springs its removed.

The accompanyingdrawings represent clear ly the manner in which my invention. is car ried into effect.

Figure 1 is an elevation of the chimney, the conical base being represented at A. Fig. 2 represents a vertical central section of the chimney, with the base inserted between the chimney-holding springs B of an Argand burner. l

The base may be more or less inclined or conical, as d sired, and the external springs between whi h it is slipped may be of any suitable length. The springs press against the conical base with the greatest force at their upper tends,f which are in contact with the most contracted portion of the conical base that their length adapt-s them to receive.

The results of this formation of the chim ney, and of the combination, with the external holding-springs, of the chimney thus formed, have been above stated and need not here be repeated.

I am aware that lamp-chimneys have been made with flaring lower ends; and this I do not broadly claim but I am not aware that a chimney for an Argand burner, having a contracted neck, a cylindrical body above the wick, and a conical or tapering base, has ever before been made. The lower part of the chimney below the contracted neck acts as the de fiector, and it is indispensable that the contracted' opening should occupy a fixed and invariable position at a certain height above the wick in order to produce a good flame. As the sides of the deflector portion of the chimney have hitherto been made perpendicular instead of inclined, it has not been possible e 2 H1L073 A slip-chimney for Argand burners, made with a contracted neck, a cylindrical body above the neck, and a conical or tapering base or deflector below the contracted neck, as and 'for the purposes shown and set forth.

In testimony whereof Ihave signed my name to this specification before two subscribing witnesses.

RUFUS S. MERRILL.

\Vitnesses:

M. BAILEY, Eon. F. BROWN. 

